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Kindergarten hail safety teaching plan

1. General knowledge of hail safety

Common sense of hail safety 1. How hail is formed and the knowledge of hail suppression.

The water on the surface of the earth is evaporated by the sun and then rises into the air. A large amount of water vapor condenses into clouds, which will liquefy when it meets cold air. With the dust in the air as the condensation core, raindrops are formed, and the raindrops are getting bigger and bigger. If there are more clouds, it will rain. If you encounter cold air without condensation nuclei, water vapor will condense into ice or snow, which is snow. If the temperature drops sharply, it will form a bigger ice mass, which is hail.

Matters needing attention in self-help

1. Pay attention to it ideologically and don't be careless in strengthening it. Know the harm of hail and take active precautions.

2. Respond calmly and improvise.

When suddenly attacked by hail, you must keep calm and take evasive measures quickly. For example, run into a bomb shelter, enter a cave, hide under a protruding rock, or temporarily hide under a dense tree. If there is nothing nearby, you should take an outdoor safety posture, that is, squat on the ground and put your head in your hands to fully protect your head, chest and abdomen from attack. If you carry a bag or folder with you, you can temporarily wear it on your head to minimize the damage. When there is really nothing, you can take off your shoes, or pick up a big stone on the ground and put it on your head, which can also play a buffering role.

3, pay attention to traffic safety If you are driving, it is best to park your car in the garage, or park on a relatively safe roadside to avoid damage to the windshield by hail. Don't get off in a hurry during the hail, in case you get hurt.

4, beware of electric shock

Stay away from lighting lines, high-voltage lines and transformers to avoid serious consequences of electric shock.

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We should have social awareness, and when we see people in need, such as children, the blind and the elderly, we should quickly rush to help them escape to a safe place; If anyone is found injured, he should be rescued immediately and call 120 ".

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Matters needing attention

Close the doors and windows.

Proper placement of outdoor items susceptible to hail and strong winds. The car had better be parked in the garage.

Kindergarten children and school students should be placed in classrooms, and outdoor activities should be suspended.

Stop outdoor activities and don't travel at will.

While preparing for hail suppression, we should also prepare for lightning protection.

2. How the hail is formed, and the knowledge of hail suppression.

The water on the surface of the earth is evaporated by the sun and then rises into the air. A large amount of water vapor condenses into clouds, which will liquefy when it meets cold air. With the dust in the air as the condensation core, raindrops are formed, and the raindrops are getting bigger and bigger. If there are more clouds, it will rain. If you encounter cold air without condensation nuclei, water vapor will condense into ice or snow, which is snow. If the temperature drops sharply, it will form a bigger ice mass, which is hail.

Matters needing attention in self-rescue 1. Pay attention to it ideologically, not casually. Know the harm of hail and take active precautions. 2, calm response, improvise to deal with the sudden hail attack, we must remain calm and take evasive measures quickly.

For example, run into a bomb shelter, enter a cave, hide under a protruding rock, or temporarily hide under a dense tree. If there is nothing nearby, you should take an outdoor safety posture, that is, squat on the ground and put your head in your hands to fully protect your head, chest and abdomen from attack.

If you carry a bag or folder with you, you can temporarily wear it on your head to minimize the damage. When there is really nothing, you can take off your shoes, or pick up a big stone on the ground and put it on your head, which can also play a buffering role.

3, pay attention to traffic safety If you are driving, it is best to park your car in the garage, or park on a relatively safe roadside to avoid damage to the windshield by hail. Don't get off in a hurry during the hail, in case you get hurt.

4, beware of electric shock to avoid away from lighting lines, high voltage wires and transformers, in order to prevent the serious consequences of electric shock. 5. Be socially conscious. When you see people in need, such as children, the blind and the elderly, you should rush to help them escape to a safe place. If anyone is found injured, he should be rescued immediately and call 120 ".

End the preventive measures and close the doors and windows. Proper placement of outdoor items susceptible to hail and strong winds.

The car had better be parked in the garage. Kindergarten children and school students should be placed in classrooms, and outdoor activities should be suspended.

Stop outdoor activities and don't travel at will. While preparing for hail suppression, we should also prepare for lightning protection.

3. Hazards caused by hail and preventive measures

Blizzard, rainstorm, fog disaster protection knowledge Blizzard and hail are more common, although they may not necessarily form disasters, we should also pay attention to protecting ourselves: l. Pay attention to adding clothes to keep warm in snowstorm days; We should reduce outdoor activities and avoid frostbite.

2. When it hails, you should avoid being indoors; If you are outdoors, use rain gear or other substitutes to protect your head and move it indoors as soon as possible to avoid injury. In a short period of time, the continuous rainstorm in an area will cause the river to rise violently, overflow dams, flood farmland and villages, and destroy roads, bridges and houses. This is a flood disaster.

How should we save ourselves when the flood comes? L under the threat of flood, if there is enough time, it should be transferred to hillside, highland and other places in an organized way according to the predetermined route; In the case of being caught off guard and surrounded by floods, we should use boats, rafts, door panels, wooden beds, etc. Let the water transfer as much as possible. 2. When the flood comes too fast to move, you should immediately climb the roof, tall buildings, big trees and high walls, take temporary shelter and wait for rescue.

Don't swim alone. In the mountainous area, if it rains continuously, it is easy to have flash floods.

In this case, we should pay attention to avoid crossing the river and being washed away by mountain torrents, and also pay attention to preventing landslides, rolling stones and mudslides. 4. It is found that the high-voltage tower is toppled, and the wires are drooping or broken; Stay away from danger, don't touch or get close to it to prevent electric shock.

5. After the flood, you should take medicine to prevent epidemic, do a good job in health and epidemic prevention, and avoid infectious diseases. To prevent the harm of fog, a large number of small water droplets or ice crystal particles are suspended in the air near the ground, which makes people's vision blurred. When the horizontal visual distance drops below 1000 meters, it is called fog.

Fog can be classified into grades. When the visible distance is less than 1000m and more than 5000m, it is called light fog. When the visible distance is less than 500 meters, it is called fog; When the visible distance is less than 200 notes, it is called dense fog. Protective measures against fog disasters Try not to go out. When you have to go out, wear a mask to prevent inhalation of toxic gases.

Try to exercise as little as possible in foggy days, and don't exercise in foggy days. Pedestrians should be careful when crossing the road and see the passing vehicles clearly.

When driving a vehicle and riding a bicycle, you should slow down and obey the traffic police's command. Don't rush by car (boat) or crowd at the ferry when you stop. How to pay attention to safety when cycling in rainy and snowy weather? When riding a bicycle in rainy and snowy weather, you should also pay attention to the following points: L. When riding in the rain, don't bury your head to avoid the rain.

2. When riding a bike in rainy days, you'd better wear a raincoat and poncho instead of riding a bike with an umbrella in one hand and a handle in the other. 3. When riding a bicycle in snowy days, don't inflate the bicycle tires too much, which will increase the friction with the ground and make it difficult to slip.

4. When riding a bike in snowy days, keep a large distance from the vehicles and pedestrians in front. 5. When riding a bike in snowy days, you should choose a flat road with no ice and shallow snow. Don't slam on the brakes, don't turn sharply, and turn as wide as possible.

6. Rain and snow. The road is muddy and slippery, so you should pay more attention when riding, and be prepared for emergencies at any time. The riding speed is slower than normal weather.

How to avoid a tornado? Tornado is a very powerful cyclone, which usually occurs in spring. Tornadoes often come very quickly and suddenly, accompanied by loud noise.

It is extremely destructive and can drag sand, trees, crops, even fish in the sea and goods in warehouses to the sky, posing a great threat to people's lives and property. How to effectively protect yourself when a tornado strikes? 1. When a tornado strikes, open the doors and windows to balance the indoor and outdoor air pressure to prevent the wind from blowing off the roof and knocking down the walls.

2. indoors, people should protect their heads and squat down facing the wall. 3. When encountering a tornado in the wild, you should quickly move in the opposite direction or sideways to avoid it.

When the tornado has reached your eyes, you should find low-lying terrain to get down, close your mouth and eyes, and protect your head with your hands and arms to prevent being hit by flying objects. 5. If you encounter a tornado while driving, get off and avoid it, and don't stay in the car.

How to save yourself when the flood breaks out? In a short period of time, the continuous rainstorm in an area will cause the river to rise violently, overflow dams, flood farmland and villages, and destroy roads, bridges and houses. This is a flood disaster. How should we save ourselves when the flood comes? L under the threat of flood, if there is enough time, it should be transferred to hillside, highland and other places in an organized way according to the predetermined route; In the case of being caught off guard and surrounded by floods, we should use boats, rafts, door panels, wooden beds, etc. Let the water transfer as much as possible.

2. When the flood comes too fast to move, you should immediately climb the roof, tall buildings, big trees and high walls, take temporary shelter and wait for rescue. Don't swim alone.

In the mountainous area, if it rains continuously, it is easy to have flash floods. In this case, we should pay attention to avoid crossing the river and being washed away by mountain torrents, and also pay attention to preventing landslides, rolling stones and mudslides.

4. It is found that the high-voltage tower is toppled, and the wires are drooping or broken; Stay away from danger, don't touch or get close to it to prevent electric shock. 5. After the flood, you should take medicine to prevent epidemic, do a good job in health and epidemic prevention, and avoid infectious diseases.

How to protect yourself from snowstorms and hail? Blizzard and hail are more common, although they may not cause disasters, we should also pay attention to protecting ourselves: L. Pay attention to adding clothes to keep warm in snowstorm days; We should reduce outdoor activities and avoid frostbite. 2. When it hails, you should avoid being indoors; If you are outdoors, use rain gear or other substitutes to protect your head and move it indoors as soon as possible to avoid injury.

How to avoid being struck by lightning when going out? Lightning is a common natural phenomenon, which is essentially a spark discharge in thunderstorm clouds in the sky. The light produced during discharge is lightning, and the loud noise produced by lightning makes the air expand rapidly when heated, which is thunder. Thunderstorms are prone to lightning strikes, causing injuries and even deaths. To avoid lightning strike, you should do: 1. When you encounter thunderstorm weather when you go out, you should avoid it in time and don't stay in the open field.

2. If there is nowhere to hide in the open field when there is lightning, you should try to find a low-lying place (such as a pit) to hide, or squat down immediately, put your feet together, put your arms around your knees, bend your head down, and try to reduce the height of your body. If there are conductive objects (such as shovels, metal umbrellas, etc.) in your hand, throw them away quickly. Never run in the wild with these objects, or you will become the target of lightning strike.

3. Be especially careful. When encountering lightning, never.

4. Knowledge about hail

hail

Hail, commonly known as hail, is the most common in summer or at the turn of spring and summer. It's some ice particles as small as mung beans and soybeans as big as chestnut eggs, and the heavy hail is bigger than grapefruit. Except for Guangdong, Hunan, Hubei, Fujian, Jiangxi and other provinces, there is less hail weather in China, and every place suffers from different degrees of hail disasters every year. Especially in the mountainous and hilly areas in the north, the terrain is complex, the weather is changeable and there are many hail, which is very harmful to agriculture. Severe hail destroys crops and houses, and people are often injured and livestock die. Therefore, hail is one of the most serious disasters in China.

How is the hail formed? What is its structure? How can we prevent hail disaster?

Brief introduction of hail

Hail is a kind of ice or ice falling from a strong cumulonimbus cloud (also called hail cloud). People usually call it "hail"

According to the size, hardness and structure, the hail falling from the hail cloud to the ground can be roughly divided into the following four types:

Hail: Ice cubes with a diameter of more than 5 mm are hard and will rebound when landing; Each hail block consists of an opaque core and transparent and opaque ice layers outside the core. This is the most harmful hail.

Soft hail: loose structure, light weight, easy to break when landing. This kind of hail is called soft hail. This kind of hail is less harmful. Soft hail usually occurs in high latitudes or plateaus. Some people think that hail in the clouds sometimes turns into soft hail because of the influence of high-altitude explosion.

Ice hockey: a small solid ice hockey or ice cube with a diameter less than 5 mm, which has a hard structure and will rebound when landing, so it is also called a small hail. It is less harmful than hail.

Columum: white or milky opaque granular solid precipitate, 2-5 mm in diameter, soft in structure and fragile when touching the ground. It is often spherical or conical, a bit like Michelle, but the diameter of Michelle is generally below1mm. ..

5. Hazards of hail

Hail falls from the clouds like rain and snow.

But the clouds that hail are very strong cumulonimbus clouds, and only very strong cumulonimbus clouds can hail. Cumulonimbus clouds, like all kinds of clouds, are formed by the rising and condensation of air near the ground.

When air rises from the ground, the air pressure decreases and the volume expands. If there is no heat exchange between the rising air and its surroundings, the air temperature will decrease, because expansion consumes energy. This temperature change is called adiabatic cooling. According to the calculation, every time the air in the atmosphere rises 100 m, the temperature will decrease by about 1 degree due to the adiabatic change.

We know that at a given temperature, there is a limit to the amount of water vapor contained in the air, and reaching this limit is called "saturation". When the temperature is lowered, the amount of water vapor that may be contained in the air will decrease. Therefore, the originally unsaturated air may reach saturation due to adiabatic cooling in the upward movement. After the air reaches saturation, excess water vapor will attach to the floating condensation nuclei in the air and form water droplets.

When the temperature is below zero degrees Celsius, excess water vapor will condense into fine ice crystals. These water droplets and ice crystals gather together and float in the air to become clouds.

There are different forms of air movement in the atmosphere, forming different forms of clouds. Clouds formed by convection include light cumulus, thick cumulus and cumulonimbus.

People call it cumulus clouds. They are isolated and upward-developing clouds, because there are upward and downward movements in convection, which often form clouds in the updraft area, become gaps in the downdraft area, and sometimes you can see the blue sky.

Cumulative clouds are different because of different convective intensities, and the sizes of clouds are also very different. If the convective movement in the cloud is weak and the updraft can't reach the condensation height, there will be no cloud, only dry convection.

If the convection is strong, it can develop into cumulus clouds. The top of cumulus clouds, like cauliflower, consists of many well-defined convex clouds, and the thickness of clouds can reach 4-5 kilometers. If the convection is intense, a cumulonimbus cloud can be formed, the cloud bottom is dark, the cloud top develops very high, reaching about 10 km, the edge of the cloud top becomes blurred, and the cloud top often expands to form an anvil.

Generally, cumulonimbus clouds may produce thunderstorms, but only when they are particularly strong, the clouds are high, there is strong rising gas in the clouds, and there is a lot of water in the clouds will hail be produced. This kind of cloud is usually called hail cloud. Hail clouds consist of water droplets, ice crystals and snowflakes.

Generally, there are three layers: the bottom layer is above 0℃ and consists of water droplets; The middle layer has a temperature of 0℃ to -20℃ and consists of supercooled water droplets, ice crystals and snowflakes. The temperature of the top layer is lower than -20℃, which is basically composed of ice crystals and snowflakes. In the hail cloud, the airflow is very strong. Usually in the direction of the cloud, a strong updraft enters from the bottom of the cloud and flows out from the top of the cloud.

There is also a downward airflow flowing in from the middle behind the cloud and out from the bottom of the cloud. This is also the precipitation area where hail usually occurs.

These two organized updrafts are connected with the airflow between the downdraft and the environment, so the airflow structure in the heavy hail cloud is relatively continuous. The strong updraft not only delivers enough water vapor to the hail cloud, but also supports the hail particles to stay in the cloud and grow to a considerable size before landing.

How does hail grow in hail clouds? In the hail cloud, the strong updraft carries many large and small water droplets and ice crystals, some of which fuse with ice crystals and freeze into larger ice particles. These particles and supercooled water droplets are transported by the updraft to the water content accumulation area, which can become the hail core. The initial growth core of these hailstones has good growth conditions in the water content accumulation area. After the hail A enters the growth area with the updraft, it collides with supercooled water droplets in the area with large water volume and low temperature, and grows into a transparent ice layer, and then enters the low temperature area with small water volume, where it is mainly composed of ice crystals, snowflakes and a small amount of supercooled water droplets, and the hail adheres to them and freezes to form an opaque ice layer.

At this time, the hail has grown up and the updraft there is weak. When it can't support the growing hail, the hail will fall in the updraft and continue to grow through the fusion of ice crystals, snowflakes and water droplets in autumn. When it falls to a higher temperature area, the supercooled water droplets that hit it will form a transparent ice layer. At this time, if it falls into another stronger updraft area, the hail will rise again and repeat the above growth process.

In this way, hail grows in transparent layer and opaque layer; Due to the differences in growth time and water content, the thickness and other characteristics of each layer are also different. Finally, when the updraft couldn't support the hail, it fell from the clouds and became the hail we saw.

= = = = = = = = = = In summer, some clouds will drop ice particles, which is hail. Hail is the product of cumulonimbus clouds, which develop very vigorously.

If we dissect a hail, we can find that its innermost part is a hail core composed of white opaque snow beads (also called graupel), and the outside is a layer of transparent and opaque ice. There are a lot of ice crystals and supercooled water droplets in the hail cloud, which condense together during the movement and become snow beads.

Snow beads are the embryos of hail. Hail embryos move up and down with the airflow in the clouds.

When they enter the area with higher temperature and more water vapor below, a water film is formed outside. Later, once the updraft is encountered, it is sent to a place where the temperature is lower than 0℃, and the water film freezes into a transparent ice shell.

If the updraft is strong, it will be sent to the upper part and contain a lot of snowflakes, ice crystals and supercooled water droplets to freeze on it. Because the temperature in the upper part of the cloud is very low, it freezes quickly, and the snowflakes, ice crystals and air contained in the water have no time to escape, forming an opaque ice layer.

The airflow in the hail cloud is stronger and weaker, so the hail embryo moves up and down again and again in the cloud, repeating the above process, forming a transparent and opaque ice room. When it grows to the point where the updraft can't support it, it plummets and becomes hail. Some hail is as soft as snow, but some hail is as hard as ice. If the falling hail is too large, it may cause harm to crops, buildings and even people, so people see hail falling from the sky.

6. What are the hazards of hail?

The biggest impact of hail disaster is the harm to agriculture, especially fragile crops such as vegetables and flowers. In addition, cases of hail wounding are also common in China. In some extreme weather, fist-sized hail falls from the sky, posing a serious threat to people's life safety.

After the surface water is evaporated and lifted into the air, the water vapor gathers together through the condensation nucleus, forming raindrops around the condensation nucleus. As the condensed water vapor gradually increases, the clouds can't hold raindrops, and raindrops fall to form rainfall. If raindrops encounter a sudden drop in temperature or extremely cold air when falling, they will stick together to form a relatively large ice mass and hail.

Extended data:

At present, with the help of advanced weather warning system, the occurrence of hail weather can be predicted, so as to do a good job of disaster prevention and mitigation in advance. For example, we can transport some catalysts, such as dry ice, to the cloud through rockets, planes and other carriers, so that the cloud can start to rain before the formation of heavy hail, thus reducing the harm of hail.

For agriculture, changing the surface environment and improving the forest coverage rate are also effective ways to reduce the hail disaster. In addition, it is also one of the more popular disaster reduction methods to cultivate hail-resistant crops through agricultural techniques such as hybridization. For people, the most effective way to reduce hail disaster is to reduce travel and stay indoors as much as possible in hail weather.